The present invention pertains generally to infrared lasers and more particularly to optically pumped infrared lasers.
Applications of laser photochemistry have produced a need for simple and efficient lasers for producing coherent radiation at specified wavelengths near 16 .mu.m. Of the various methods and devices utilized for producing these specified wavelengths, including stimulated Raman scattering of selected gases and various types of solid state devices for either producing specified wavelengths or shifting frequency, such as the diode laser and various germanium substrates, respectively, the gas lasers are the most attractive candidates for providing these specified wavelengths because of their simplicity, efficiency, and scalability, in both power and repetition rate. Currently, however, conventional gas lasers, such as CO.sub.2 lasers, are incapable of producing specified frequencies of interest. Although the CO.sub.2 laser has been useful in producing near 16 .mu.m radiation by the various methods disclosed above, these systems have been extremely complex with low overall efficiency, rendering these approaches somewhat impractical for uses outside the laboratory.
With the advent of optically pumped lasers, the highly developed technology of CO.sub.2 lasers has been applied in an optical pumping scheme for producing transitions in another molecular gas causing inversions in the optically pumped gas at desired wavelengths near 16 .mu.m. The problem, however, in producing such a system is selecting a gas having an absorption spectrum which falls within the operating range of a line tunable CO.sub.2 laser and which, according to selection rules, inverts between quantum states to produce the desired wavelengths. Additionally, conversion gains between quantum levels must necessarily be considered to produce an optically pumped laser having sufficient gain.